gas tank sending unit

[quik8outlaw]

Is there a way I can check a sending unit to see if the gauge works with it before I install it ??

[clapage6]

Originally Posted by quik8outlaw

Is there a way I can check a sending unit to see if the gauge works with it before I install it ??

sure, yeah just plug it in really. then ground the sending unit. check gauge. then remove ground for sending unit and check gauge again.

i forget which one is full and empty right now..

[motornut]

could wire it up with longer test wires.move it manually?
but grounding the "sender" wire , should read empty
sender left off, should read over full.

[cadillac_al]

You hook the brown wire to the sending unit as normal and press the sending unit against the side of the gas tank or the frame to complete the ground. Then you move the float to see if the gauge moves.

[quik8outlaw]

thanks for the help

[wilkin250r]

You can hook it up, sure. If you want to test either one individually, you need a few things. A multi-meter to measure resistance to check the sending unit, and a few resistors ($2 at your local Radio Shack. Not $2 each, $2 total for several) and some jumper wires to connect it all.

Your fuel sending unit is just a resistance measurement. Using your multimeter, you can measure zero ohms (or close to it) when the float is all the way down in the "empty" position. It will read about 45 ohms at half full, and about 90 ohms at full.

To test the gauge without the sending unit, you just use jumper wires to hook up resistors. Hook up 45 ohms from the sending wire to ground, the gauge should read half full. Hook up 30 ohms, it should read about 1/3 full, hook up 90 ohms and the gauge should read full. The gauge isn't instant (otherwise it would be bouncing everywhere as the fuel in the tank sloshed around) so give the gauge time to adjust.

If you DO try the resistors, just realize that you might not be able to find a "45 ohm", you might only find a 51 ohm. So you'll read a hair over half full. The closest you might find to 30 is 33. But make sure it's "33 ohm" and not "33k ohm". That "k" is 1000, so it's actually 33,000 ohm, which will peg your gauge way past full (but won't break it, don't worry)